摘要
利用密度泛函理论 (DFT)和从头算 (abinitio)研究了CH3 S CH2 SH互异化的反应机理 .采用HF、B3LYP、MP2理论水平和中等基组 6 31(d) ,计算了CH3 S、CH2 SH及其过渡态的结构参数、谐振频率、零点能(ZPE)、总能量和相对能量 ,并利用B3LYP/ 6 31(d)的方法计算了反应的内禀反应坐标 (IRC) ,给出了分子构型和自旋污染沿反应坐标的变化曲线 ,以及最小能量曲线 (MEP)、绝热能量曲线 .此外 ,利用传统过渡态理论(CTST)研究了该互异化反应的速率常数和平衡常数在 2 0 0～ 10 0
The tautomeric reaction of CH 3S CH 2SH has been studied by using the Density Function Theory(DFT) and Molecular Orbital(MO) ab initio. The geometries, frequencies, zero point energies(ZPE), total energies and relative energies of CH 3S, CH 2SH and Transition state(Ts) have been calculated on HF/B3LYP/MP2 theory levels with basis set 6-31G(d), respectively. In order to obtain the credibilitive vibration frequencies, ZPE, total energies, vibration frequencies analysis has been performed. Ts has been confirmed by the two criterions: Firstly, only one imaginary vibration frequency is in existence; secondly, Internal Reaction Coordinate(IRC) has been confirmed to connect the reactant and the product. At the same time, IRC was calculated based on the B3LYP theory level with the medium basis set 6-31G(d). The kinetic mechanism and properties of the tautomeric reaction have been studied in detail. In addition, the geometry parameters and spin contamination along IRC are discussed. From the calculated results of IRC, the Minimum Energy Potential(MEP) curve and the adiabatic energy potential curve were obtained. Participation functions and activation energy have been obtained from the result of Gaussian98 output on the B3LYP theory level and basis set 6-31G(d). On the basis of the result of Gaussian98 output, the rate constants and equlibrium constants from 200 K to 1000 K have been calculated by Conventional Transitional State Theory(CTST).
基金
国家自然科学基金资助项目 (2 0 0 730 4 2 )
关键词
互异化反应
反应机理
自旋污染
速率常数
Tautomeric reaction, Reaction mechanism, Spin contamination, Rate constant
